As prior arts of this field, there are two Korean patents. One of them is a patent application having a filing number 10-2003-56410 filed by the applicant of this invention and the other is a patent having a registration number 10-0465346 of Hamamatsu Photonics Co., Ltd of Japan.
As shown in said cited references, it was very difficult to install the electrostatic eliminator according to the prior arts at the limited space. And it was difficult to change the installed position according to the change of the production line.
The biggest problem was a limited space and the next ones were that removal and reinstalling of them were not easy. Moreover it was difficult to fix the installation angle in order that the ions from the head unit are emitted toward the charged body exactly. Therefore, generally it was installed on the ceiling by using a specially prepared bracket, but installing by readjusting the position of a number of electrostatic eliminators one by one in production line was very difficult.
The main reason was the head from which the +ions and −ions come out toward the charged body was attached at the body i.e. the case of the electrostatic eliminator as one body. Accordingly it was impossible to solve this problem actually with the structure of the prior electrostatic eliminator.
For these reasons, efforts to solve this problem has been made at the semiconductor factories, LCD production lines, PDP production lines, OLED production lines and the like, but no radical solution has been found so far.
Meanwhile the X-ray is divided into soft X-ray and hard X-ray according to the material permeability, the soft X-ray has low permeability and is absorbed easily though the air space is thin and the hard X-ray has high permeability and is used in taking a Roentgen photograph.
The energy of the soft X-ray is very low (approximately 1/3,000 of that of the hard X-ray) so the permeability is very low and it is absorbed mostly in the air.